This part aims to summarise the available data on the numbers and distribution of each species of wildfowl in Britain. A brief description of the birds’ behaviour and feeding habits is given first since this is very relevant to the interpretation of their distribution. There are a total of 48 wildfowl on the British List (549, and later reports in The Ibis); most are predominantly winter visitors. Thirty-one species occur here commonly, and these are fully treated in the following accounts. The remainder are either sporadic in occurrence or are usually in small numbers; they are considered in less detail, at the end of the accounts. The British List includes four species introduced to Britain and now well established, although two, the Egyptian Goose and Mandarin Duck, are in relatively restricted areas. The Canada Goose, on the other hand, is very widespread in England and Wales. It, and the Ruddy Duck, continue to increase in numbers and to expand their range (406, see also p.460).

Wildfowl are widely kept in captivity and several other species have been seen in the wild in Britain from time to time although recognised as originating from captive stock. Among these are the Black Swan (Cygnus atratus), Bar-headed Goose (Anser indicus), Ross7 Goose (Anser rossi), Carolina or Wood Duck (Aix sponsa) and Ringed Teal (Calonetta leucophyrus). These are not likely to become widely established and recent legislation (p.539) makes further introductions more difficult.

The Solway Basin

The Solway Basin, lying partly in England and partly in Scotland, is deservedly famous for its large and widespread population of geese, for its great expanses of foreshore and merse, for its popularity as a wildfowling centre, and for the various conservation measures, both formal and informal, which may have helped to correct the earlier trend towards excessive shooting. Over the past half century the changing pattern of disturbance has had a marked effect on the local distribution of the geese, but taken as a whole the peak numbers within the region are now larger than ever before. Whooper Swans are also plentiful, but in common with the ducks the concentrations at any one place are seldom outstandingly large.

Although the firth is the primary centre of interest, the numerous inland waters and marshes are frequently used in preference to the coast, and together support a sizeable population of breeding and wintering wildfowl. Many of the more important sites are now protected to a greater or lesser degree, either by the owners or by one of the voluntary bodies, such as the RSPB, the Scottish Wildlife Trust and the Cumbria Trust for Nature Conservation. Statutory reserves are also established on Siddick Pond, near Workington, on the Castle and Hightae Lochs, Lochmaben, and on the merse and foreshore at Caerlaverock, by Dumfries.

Inland waters of north Cumbria

The inland waters on the English side of the firth have much in common with those in south Lakeland, and carry a similar population of breeding and wintering ducks. Greylags and Whooper Swans also winter in some numbers, and there is in addition a feral population of several hundred Greylags and Canada Geese.

The natural history of ant–plant mutualisms has fascinated Western scientists for roughly two centuries. During this time it has become clear that the ways in which plants manipulate ants, and vice versa, can be so complex and subtle as to severely stretch the credence of the observer. The early natural historians described ant–plant relationships in superb detail, but generally inferred that a given relationship was mutualistic from anatomical, morphological, or behavioral data alone. Experimental verification was the exception rather than the rule. Although the experimental approach was tried by a few early workers, such as von Wettstein (1889), its impact was not dramatic until the publication of Janzen's seminal work on acacia ants about twenty years ago. This pioneering research has since been followed by many excellent experimental field studies embracing a variety of ant–plant mutualisms from many kinds of environments. Our knowledge of the selective pressures that produce the mutualistic response, the dynamics of the ant–plant interactions, the benefits to the plants and the ants, and the ways that mutualisms evolve has been vastly improved. At the same time, ant–plant mutualisms are extremely numerous and varied, and so far only a very few cases have been adequately analyzed. As a consequence, generalizations from limited data often have to be made. Whether or not this is wise will be revealed as new studies are published.

Ideas and syntheses generally enter the mind as a result of the stimulation of colleagues.

In a world flora that harbors pollinators as diverse as slugs, mosquitoes, honey-possums, hummingbirds, and thrips; involving mechanisms as bizarre as pseudocopulation, pseudoaggression, and floral fermentation; and with reproductive structures as simple and ephemeral as the buttercup or as complex and long-lived as the Banksia inflorescence, it is very strange indeed that ants have not played a greater part. There are very few well-documented cases of pollination by ants. On the contrary, ants are widely regarded as thieves, parasitizing plants by taking floral rewards intended for pollinators, without performing the movements necessary for pollination (McDade & Kinsman 1980; Wyatt 1981; Fritz & Morse 1981; Willmer & Corbet 1981; Schaffer et al. 1983), or by simply chewing floral organs such as the style and ovary (Galen 1983).

Ant pollination has been reported a number of times: Herniaria ciliolata (Proctor & Yeo 1973), Orthocarpus pusillus (Kincaid 1963), Polygonum cascadense (Hickman 1974), Glaux maritima (Dahl & Hadac 1940), Seseli libanotis (Hagerup 1943), Morinda royoc, Cordia brownei (Percival 1974), Rohdea japonica (Migliorato 1910; but disputed by van der Pijl 1955), and Microtis parviflora (Armstrong 1979). Diamorpha smallii (Crassulaceae) was studied by Wyatt (1981) and Wyatt and Stoneburner (1981), who showed that this diminutive plant is also pollinated by ants, especially Formica shaufussi and F. subsericea. Pollen adheres to the hairs and integumental sculpturing of these ant species. They visit the flowers systematically but the degree of dependence on ant-borne pollen for seed set remains unknown.

Ants foraging on plants take a great variety of prey items including insects and other invertebrates that are either herbivores or seed predators. Therefore, the mere presence of hunting foragers can provide some defense against plant enemies. With few exceptions plants are hospitable foraging areas, and once ants have gained access, they will hunt and remove prey irrespective of the size, architecture, or morphology of the plant. Ants remove a great variety of animals that do damage even, as in the case of Monomorium floricola, entering the tunnels of leaf-mining beetles to kill the tiny occupants (Taylor 1937).

The protective character of ants foraging on plants has been recognized for hundreds of years. In various parts of China nests of the weaver ant Oecophylla smaragdina were taken from the forest around citrus and litchi groves and placed on branches of orchard trees. Branches close to the nest were smeared with wax to prevent the ants from leaving the trees, and until they established their food-gathering territory their diet was augmented with dog intestines or silkworm larvae. After several weeks the ants established territories and patrolled the trees aggressively for food. Bamboo poles were used to create bridges from trees with nests to those without, and the groves were soon a mosaic of Oecophylla territories. As long ago as the eleventh century A.D., the Chinese observed the ants removing a considerable variety of insect herbivores and seed predators in large numbers, including stinkbugs of the hemipteran family Pentatomidae, many of which feed on plant sap, and the larvae of the butterfly Papilio demoleus, which were killed by workers stretching the unfortunate victim in several different directions simultaneously and holding it in that position until it died.